Luminescence characteristics of Sm3+-doped lithium barium gadolinium silicate glasses for Orange LED's.

Abstract

Traditional melt-quenching technique is adopted for synthesis of Sm2O3 doped lithium barium gadolinium silicate (LBGS: Li2O-BaO-Gd2O3-SiO2) glasses. These glass samples are characterized by different spectroscopic techniques under ambient conditions. Density and molar volume of the present LBGS glass samples increase with increasing Sm3+ ion-concentration. JO intensity parameters Ωλ (where λ = 2, 4 and 6) are evaluated by using Judd-Ofelt theory and Ω4 > Ω2 > Ω6 trend is observed. Furthermore, these parameters are used to evaluate radiative properties like radiative transition probability, branching ratio, radiative lifetime and stimulated emission cross-section for state 4G5/2 of Sm3+ ion. The measured color coordinates for the title glass fall within orange region of CIE diagram. For the present LBGS glasses, the correlated color temperature values are less than warm. The lifetime for the 4G5/2 decreases from 2.468 to 0.566 ms when concentration increases from 0.1 to 2.0 mol% of Sm3+ ions. The analysis of non-exponential behavior of the decay profile through Inokuti-Hirayama model for S = 6 indicates that the energy transfer between Sm3+ ions is due to dipole-dipole interactions. Further energy transfer parameters (Q), critical distance (Ro, Å) and donor-acceptor interaction parameters (CDA x 10-40 cm6/s) of Sm3+ ions doped LBGS glasses were evaluated and compared to other glasses. From the evaluated results it is suggested that the present novelty of the work emphasizes on new matrix LBGS doped with Sm3+ ions showing increasing energy transfer rate with increasing in concentration of Sm2O3 content indicating these glasses are potential candidate for orange-light emitting device applications.